Hendra Virus Research Articles

Landscape and age dynamics of immune cells in the Egyptian rousette bat.

Bats harbor high-impact zoonotic viruses often in the absence of disease manifestation. This restriction and disease tolerance possibly rely on specific immunological features. In-depth molecular characterization of cellular immunity and imprinting of age on leukocyte compartments remained unexplored in bats. We employ single-cell RNA sequencing (scRNA-seq) and establish immunostaining panels to characterize the immune cell landscape in juvenile, subadult, and adult Egyptian rousette bats (ERBs). Transcriptomic and flow cytometry data reveal conserved subsets and substantial enrichments of CD79a+ B cells and CD11b+ Tcells in juvenile animals, whereas neutrophils, CD206+ myeloid cells, and CD3+ Tcells dominate as bats reach adulthood. Despite differing frequencies, phagocytosis of circulating and tissue-resident myeloid cells and proliferation of peripheral and splenic lymphocytes are analogous in juvenile and adult ERBs. We provide a comprehensive map of the immune landscape in ERBs and show age-imprinted resilience progression and find that variability in cellular immunity only partly recapitulates mammalian archetypes.

Henipavirus sero-surveillance in horses and pigs from Northern Nigeria

Hendra virus and Nipah virus are considered to be emerging viruses and cause severe zoonotic diseases, which occur in humans who have had close contact with horses and pigs in Australia and Asia, respectively. Both viruses belong to the genus Henipavirus. Although there are large populations of horses and pigs in northern Nigeria, no previous studies in this region have investigated henipavirus sero-surveillance in horses and pigs using the gold standard test, the serum neutralization test (SNT). A total of 536 apparently healthy horses and 508 apparently healthy pigs were sampled in northern Nigeria in 2018. Serum samples were tested for Hendra virus and Nipah virus-specific antibodies using either the Henipavirus Luminex binding assays for horses or the Hendra virus Competitive ELISA and Nipah virus Indirect ELISA for pigs as initial screening tests, followed by the confirmatory Hendra and Nipah virus SNT for both species, according to accredited protocols at the Australian Centre for Disease Preparedness. Although some horse and pig samples crossed-reacted or reacted weakly in the screening test, confirmatory SNT for all of them proved negative. This study reveals the absence of Hendra and Nipah antibodies in horses and pigs in northern Nigeria, which is consistent with the absence of observable disease in the field. However, the continuous inter and intra-trans-boundary animal movement and trade in Nigeria calls for the continuous evaluation of the henipavirus status of susceptible animals to safeguard both animal and human health.

Novel variant Hendra virus genotype 2 infection in a horse in the greater Newcastle region, New South Wales, Australia

In October 2021, the first contemporary detection of Hendra virus genotype 2 (HeV-g2) was made by veterinary priority disease investigation in a horse near Newcastle, New South Wales, Australia, as part of routine veterinary priority disease surveillance.This discovery followed an update of Hendra virus diagnostic assays following retrospective identification of this variant from 2015 via sentinel emerging infectious disease research, enabling timely detection of this case. The sole infected horse was euthanized in moribund condition. As the southernmost recognised HeV spill-over detection to date, it extends the southern limit of known cases by approximately 95 km. The event occurred near a large urban centre, characterised by equine populations of diverse type, husbandry, and purpose, with low HeV vaccination rates.Urgent multi-agency outbreak response involved risk assessment and monitoring of 11 exposed people and biosecurity management of at-risk animals. No human or additional animal cases were recognised.This One Health investigation highlights need for research on risk perception and strategic engagement to support owners confronted with the death of companion animals and potential human exposure to a high consequence virus. The location and timing of this spill-over event diverging from that established for prototype HeV (HeV-g1), highlight benefit in proactive One Health surveillance and research activities that improve understanding of dynamic transmission and spill-over risks of both HeV genotypic lineages and related but divergent emerging pathogens.

Detection of Nipah and Hendra Viruses Using Recombinant Human Ephrin B2 Capture Virus in Immunoassays.

Nipah virus (NiV) and Hendra virus (HeV) are classified as high-consequence zoonotic viruses characterized by high pathogenicity and high mortality in animals and humans. Rapid diagnosis is essential to containing the outbreak. In this study, the henipavirus receptor ephrin B2 was examined to determine whether it could be used as a universal ligand for henipavirus detection in immunoassays. Enzyme-linked immunosorbent assays (ELISAs) were developed using recombinant ephrin B2 as the capture ligand and two monoclonal antibodies (mAbs) as detection reagents. Using mAb F27NiV-34, which cross-reacts with NiV and HeV, we were able to detect NiV and HeV, while mAb F20NiV-65 was used to detect NiV. Therefore, using these two ELISAs, we were able to differentiate between NiV and HeV. Furthermore, we developed a rapid lateral flow strip test for NiV detection using ephrin B2 as the capture ligand combined with mAb F20NiV-65 as the detector. Taken together, our results show that the combination of ephrin B2 and a specific mAb provides an excellent pairing for NiV and HeV detection.

Establishment of a Captive Cave Nectar Bat (Eonycteris spelaea) Breeding Colony in Singapore.

Bats are known natural reservoirs of several highly pathogenic zoonotic viruses, including Hendra virus, Nipah virus, rabies virus, SARS-like coronaviruses, and suspected ancestral reservoirs of SARS-CoV-2 responsible for the ongoing COVID-19 pandemic. The capacity to survive infections of highly pathogenic agents without severe disease, together with many other unique features, makes bats an ideal animal model for studying the regulation of infection, cancer, and longevity, which is likely to translate into human health outcomes. A key factor that limits bat research is lack of breeding bat colonies. To address this need, a captive bat colony was established in Singapore from 19 wild-caught local cave nectar bats. The bats were screened for specific pathogens before the start of captive breeding. Custom-made cages and an optimized diet inclusive of Wombaroo dietary formula, liquid diet, and supplement of fruits enabled the bats to breed prolifically in our facility. Cages are washed daily and disinfected once every fortnight. Bats are observed daily to detect any sick bat or abnormal behavior. In addition, bats undergo a thorough health check once every 3 to 4 mo to check on their overall wellbeing, perform sampling, and document any potential pregnancy. The current colony houses over 80 bats that are successfully breeding, providing a valuable resource for research in Singapore and overseas.

Potent monoclonal antibody–mediated neutralization of a divergent Hendra virus variant

Hendra virus (HeV) and Nipah virus (NiV) are deadly zoonotic Henipaviruses (HNVs) responsible for recurrent outbreaks in humans and domestic species of highly fatal (50 to 95%) disease. A HeV variant (HeV-g2) of unprecedented genetic divergence has been identified in two fatally diseased horses, and in two flying fox species in regions of Australia not previously considered at risk for HeV spillover. Given the HeV-g2 divergence from HeV while retaining equivalent pathogenicity and spillover potential, understanding receptor usage and antigenic properties is urgently required to guide One Health biosecurity. Here, we show that the HeV-g2 G glycoprotein shares a conserved receptor tropism with prototypic HeV and that a panel of monoclonal antibodies recognizing the G and F glycoproteins potently neutralizes HeV-g2– and HeV G/F–mediated entry into cells. We determined a crystal structure of the Fab fragment of the hAH1.3 antibody bound to the HeV G head domain, revealing an antigenic site associated with potent cross-neutralization of both HeV-g2 and HeV. Structure-guided formulation of a tetravalent monoclonal antibody (mAb) mixture, targeting four distinct G head antigenic sites, results in potent neutralization of HeV and HeV-g2 and delineates a path forward for implementing multivalent mAb combinations for postexposure treatment of HNV infections.

Serological Hendra Virus Diagnostics Using an Indirect ELISA-Based DIVA Approach with Recombinant Hendra G and N Proteins.

Since the identification of Hendra virus (HeV) infections in horses in Australia in 1994, more than 80 outbreaks in horses have been reported, and four out of seven spillover infections in humans had a fatal outcome. With the availability of a subunit vaccine based on the HeV-Glycoprotein (HeV-G), there is a need to serologically Differentiate the Infected from the Vaccinated Animals (DIVA). We developed an indirect ELISA using HeV-G expressed in Leishmania tarentolae and HeV-Nucleoprotein (HeV-N) expressed in recombinant baculovirus-infected insect cells as antigens. During evaluation, we tested panels of sera from naïve, vaccinated and infected horses that either originated from a Hendra-virus free region, or had been pre-tested in validated diagnostic tests. Our data confirm the reliability of this approach, as HeV-N-specific antibodies were only detected in sera from infected horses, while HeV-G-specific antibodies were detected in infected and vaccinated horses with a high level of specificity and sensitivity. Given the excellent correlation of data obtained for German and Australian HeV-negative horses, we assume that this test can be applied for the testing of horse serum samples from a variety of geographical regions.

Morphological and quantitative analysis of leukocytes in free-living Australian black flying foxes (Pteropus alecto)

The black flying fox (Pteropus alecto) is a natural reservoir for Hendra virus, a paramyxovirus that causes fatal infections in humans and horses in Australia. Increased excretion of Hendra virus by flying foxes has been hypothesized to be associated with physiological or energetic stress in the reservoir hosts. The objective of this study was to explore the leukocyte profiles of wild-caught P. alecto, with a focus on describing the morphology of each cell type to facilitate identification for clinical purposes and future virus spillover research. To this end, we have created an atlas of images displaying the commonly observed morphological variations across each cell type. We provide quantitative and morphological information regarding the leukocyte profiles in bats captured at two roost sites located in Redcliffe and Toowoomba, Queensland, Australia, over the course of two years. We examined the morphology of leukocytes, platelets, and erythrocytes of P. alecto using cytochemical staining and characterization of blood films through light microscopy. Leukocyte profiles were broadly consistent with previous studies of P. alecto and other Pteropus species. A small proportion of individual samples presented evidence of hemoparasitic infection or leukocyte morphological traits that are relevant for future research on bat health, including unique large granular lymphocytes. Considering hematology is done by visual inspection of blood smears, examples of the varied cell morphologies are included as a visual guide. To the best of our knowledge, this study provides the first qualitative assessment of P. alecto leukocytes, as well as the first set of published hematology reference images for this species.

A Short Review on Hendra Virus

In our daily life we are exposed to different viruses and sometimes they also infect the human body. At times, they even cause life-threatening illnesses, which can put our lives in jeopardy. Also, some viruses exist which can enter the human body from animals are known as 'zoonotic viruses'. Hendra virus is also a zoonotic virus which comes under genus of 'henipavirus' and family 'paramyxoviridae'. This virus is identified during 1994-2010 outbreak of hendra virus in horses and humens at suburb of brisbane, Australia, that time out of 21, 14 horses and one humen is dead due to respiratory disease. This virus shares its genus with nipah virus. The major reservoir of this virus was found in flying foxes (Bats from the genus pteropus). This review article mainly emphasize on the structure, epidemiology, pathogenesis, diagnosis, treatment, sign and symptoms of hendra virus.

Climate Anomalies and Spillover of Bat-Borne Viral Diseases in the Asia-Pacific Region and the Arabian Peninsula.

Climate variability and anomalies are known drivers of the emergence and outbreaks of infectious diseases. In this study, we investigated the potential association between climate factors and anomalies, including El Niño Southern Oscillation (ENSO) and land surface temperature anomalies, as well as the emergence and spillover events of bat-borne viral diseases in humans and livestock in the Asia–Pacific region and the Arabian Peninsula. Our findings from time series analyses, logistic regression models, and structural equation modelling revealed that the spillover patterns of the Nipah virus in Bangladesh and the Hendra virus in Australia were differently impacted by climate variability and with different time lags. We also used event coincidence analysis to show that the emergence events of most bat-borne viral diseases in the Asia–Pacific region and the Arabian Peninsula were statistically associated with ENSO climate anomalies. Spillover patterns of the Nipah virus in Bangladesh and the Hendra virus in Australia were also significantly associated with these events, although the pattern and co-influence of other climate factors differed. Our results suggest that climate factors and anomalies may create opportunities for virus spillover from bats to livestock and humans. Ongoing climate change and the future intensification of El Niño events will therefore potentially increase the emergence and spillover of bat-borne viral diseases in the Asia–Pacific region and the Arabian Peninsula.

Novel Roles of the Nipah Virus Attachment Glycoprotein and Its Mobility in Early and Late Membrane Fusion Steps.

ABSTRACTThe Paramyxoviridae family comprises important pathogens that include measles (MeV), mumps, parainfluenza, and the emerging deadly zoonotic Nipah virus (NiV) and Hendra virus (HeV). Paramyxoviral entry into cells requires viral-cell membrane fusion, and formation of paramyxoviral pathognomonic syncytia requires cell-cell membrane fusion. Both events are coordinated by intricate interactions between the tetrameric attachment (G/H/HN) and trimeric fusion (F) glycoproteins. We report that receptor binding induces conformational changes in NiV G that expose its stalk domain, which triggers F through a cascade from prefusion to prehairpin intermediate (PHI) to postfusion conformations, executing membrane fusion. To decipher how the NiV G stalk may trigger F, we introduced cysteines along the G stalk to increase tetrameric strength and restrict stalk mobility. While most point mutants displayed near-wild-type levels of cell surface expression and receptor binding, most yielded increased NiV G oligomeric strength, and showed remarkably strong defects in syncytium formation. Furthermore, most of these mutants displayed stronger F/G interactions and significant defects in their ability to trigger F, indicating that NiV G stalk mobility is key to proper F triggering via moderate G/F interactions. Also remarkably, a mutant capable of triggering F and of fusion pore formation yielded little syncytium formation, implicating G or G/F interactions in a late step occurring post fusion pore formation, such as the extensive fusion pore expansion required for syncytium formation. This study uncovers novel mechanisms by which the G stalk and its oligomerization/mobility affect G/F interactions, the triggering of F, and a late fusion pore expansion step—exciting novel findings for paramyxoviral attachment glycoproteins.

Novel Hendra Virus Variant Circulating in Black Flying Foxes and Grey-Headed Flying Foxes, Australia

A novel Hendra virus variant, genotype 2, was recently discovered in a horse that died after acute illness and in Pteropus flying fox tissues in Australia. We detected the variant in flying fox urine, the pathway relevant for spillover, supporting an expanded geographic range of Hendra virus risk to horses and humans.

Architecture and antigenicity of the Nipah virus attachment glycoprotein

Nipah virus (NiV) and Hendra virus (HeV) are zoonotic henipaviruses (HNVs) responsible for outbreaks of encephalitis and respiratory illness. The entry of HNVs into host cells requires the attachment (G) and fusion (F) glycoproteins, which are the main targets of antibody responses. To understand viral infection and host immunity, we determined a cryo-electron microscopy structure of the NiV G homotetrameric ectodomain in complex with the nAH1.3 broadly neutralizing antibody Fab fragment. We show that a cocktail of two nonoverlapping G-specific antibodies neutralizes NiV and HeV synergistically and limits the emergence of escape mutants. Analysis of polyclonal serum antibody responses elicited by vaccination of macaques with NiV G indicates that the receptor binding head domain is immunodominant. These results pave the way for implementing multipronged therapeutic strategies against these deadly pathogens.

Structural Dynamics of the C-terminal X Domain of Nipah and Hendra Viruses Controls the Attachment to the C-terminal Tail of the Nucleocapsid Protein

To understand the dynamic interactions between the phosphoprotein (P) and the nucleoprotein (N) within the transcription/replication complex of the Paramyxoviridae and to decipher their roles in regulating viral multiplication, we characterized the structural properties of the C-terminal X domain (PXD) of Nipah (NiV) and Hendra virus (HeV) P protein. In crystals, isolated NiV PXD adopted a two-helix dimeric conformation, which was incompetent for binding its partners, but in complex with the C-terminal intrinsically disordered tail of the N protein (NTAIL), it folded into a canonical 3H bundle conformation. In solution, SEC-MALLS, SAXS and NMR spectroscopy experiments indicated that both NiV and HeV PXD were larger in size than expected for compact proteins of the same molecular mass and were in conformational exchange between a compact three-helix (3H) bundle and partially unfolded conformations, where helix α3 is detached from the other two. Some measurements also provided strong evidence for dimerization of NiV PXD in solution but not for HeV PXD. Ensemble modeling of experimental SAXS data and statistical-dynamical modeling reconciled all these data, yielding a model where NiV and HeV PXD exchanged between different conformations, and where NiV but not HeV PXD formed dimers. Finally, recombinant NiV comprising a chimeric P carrying HeV PXD was rescued and compared with parental NiV. Experiments carried out in cellula demonstrated that the replacement of PXD did not significantly affect the replication dynamics while caused a slight virus attenuation, suggesting a possible role of the dimerization of NiV PXD in viral replication.

Novel Hendra Virus Variant Detected by Sentinel Surveillance of Horses in Australia.

We identified and isolated a novel Hendra virus (HeV) variant not detected by routine testing from a horse in Queensland, Australia, that died from acute illness with signs consistent with HeV infection. Using whole-genome sequencing and phylogenetic analysis, we determined the variant had ≈83% nt identity with prototypic HeV. In silico and in vitro comparisons of the receptor-binding protein with prototypic HeV support that the human monoclonal antibody m102.4 used for postexposure prophylaxis and current equine vaccine will be effective against this variant. An updated quantitative PCR developed for routine surveillance resulted in subsequent case detection. Genetic sequence consistency with virus detected in grey-headed flying foxes suggests the variant circulates at least among this species. Studies are needed to determine infection kinetics, pathogenicity, reservoir-species associations, viral-host coevolution, and spillover dynamics for this virus. Surveillance and biosecurity practices should be updated to acknowledge HeV spillover risk across all regions frequented by flying foxes.

Henipaviruses-A constant threat to livestock and humans.

In this review, we highlight the risk to livestock and humans from infections with henipaviruses, which belong to the virus family Paramyxoviridae. We provide a comprehensive overview of documented outbreaks of Nipah and Hendra virus infections affecting livestock and humans and assess the burden on the economy and health systems. In an increasingly globalized and interconnected world, attention must be paid to emerging viruses and infectious diseases, as transmission routes can be rapid and worldwide.

Architecture and antigenicity of the nipah virus attachment glycoprotein

Nipah virus (NiV) and Hendra virus (HeV) are highly pathogenic zoonotic henipaviruses (HNVs) responsible for recurrent outbreaks of encephalitis and respiratory illness. As the current COVID-19 pandemic is gradually waning, attention is now being refocused on the nature of the next viral pandemic might be and what preparedness measures could be taken. Among almost all these discussions, the NiV Bangladesh strain (NiV-B) has been at the forefront of such concern by the scientific community, including the WHO and the Coalition for Epidemic Preparedness Innovations (CEPI).

Discovery and Evolutionary Analysis of a Novel Bat-Borne Paramyxovirus.

Paramyxoviruses are a group of RNA viruses, such as mumps virus, measles virus, Nipah virus, Hendra virus, Newcastle disease virus, and parainfluenza virus, usually transmitted by airborne droplets that are predominantly responsible for acute respiratory diseases. In this paper, we identified a novel paramyxovirus belonging to genus Jeilongvirus infecting 4/112 (3.6%) bats from two trapping sites of Hainan Province of China. In these animals, the viral RNA was detected exclusively in kidney tissues. This is the first full-length Jeilongvirus genome (18,095 nucleotides) from bats of genus Hipposideros, which exhibits a canonical genome organization and encodes SH and TM proteins. Results, based on phylogenic analysis and genetic distances, indicate that the novel paramyxovirus formed an independent lineage belonging to genus Jeilongvirus, representing, thus, a novel species. In addition, the virus-host macro-evolutionary analysis revealed that host-switching was not only a common co-phylogenetic event, but also a potential mechanism by which rats are infected by bat-origin Jeilongvirus through cross-species virus transmission, indicating a bat origin of the genus Jeilongvirus. Overall, our study broadens the viral diversity, geographical distribution, host range, and evolution of genus Jeilongvirus.

Discovery of Potential Antiviral Compounds against Hendra Virus by Targeting Its Receptor-Binding Protein (G) Using Computational Approaches.

Hendra virus (HeV) belongs to the paramyxoviridae family of viruses which is associated with the respiratory distress, neurological illness, and potential fatality of the affected individuals. So far, no competitive approved therapeutic substance is available for HeV. For that reason, the current research work was conducted to propose some novel compounds, by adopting a Computer Aided Drug Discovery approach, which could be used to combat HeV. The G attachment Glycoprotein (Ggp) of HeV was selected to achieve the primary objective of this study, as this protein makes the entry of HeV possible in the host cells. Briefly, a library of 6000 antiviral compounds was screened for potential drug-like properties, followed by the molecular docking of short-listed compounds with the Protein Data Bank (PDB) structure of Ggp. Docked complexes of top two hits, having maximum binding affinities with the active sites of Ggp, were further considered for molecular dynamic simulations of 200 ns to elucidate the results of molecular docking analysis. MD simulations and Molecular Mechanics Energies combined with the Generalized Born and Surface Area (MMGBSA) or Poisson–Boltzmann and Surface Area (MMPBSA) revealed that both docked complexes are stable in nature. Furthermore, the same methodology was used between lead compounds and HeV Ggp in complex with its functional receptor in human, Ephrin-B2. Surprisingly, no major differences were found in the results, which demonstrates that our identified compounds can also perform their action even when the Ggp is attached to the Ephrin-B2 ligand. Therefore, in light of all of these results, we strongly suggest that compounds (S)-5-(benzylcarbamoyl)-1-(2-(4-methyl-2-phenylpiperazin-1-yl)-2-oxoethyl)-6-oxo-3,6-dihydropyridin-1-ium-3-ide and 5-(cyclohexylcarbamoyl)-1-(2-((2-(3-fluorophenyl)-2-methylpropyl)amino)-2-oxoethyl)-6-oxo-3,6-dihydropyridin-1-ium-3-ide could be considered as potential therapeutic agents against HeV; however, further in vitro and in vivo experiments are required to validate this study.

Hendra virus

This datasheet on Hendra virus covers Identity, Distribution, Hosts/Species Affected.